Vacuum cleaner head



VACUUM CLEANER HEAD Filed April 16, 1964 3 Sheets-Sheet 1 III I HANSWESSEL INVENTOR.

w A Q Attorney Feb. 22, 1966 H. WESSEL 3,235,899

VACUUM CLEANER HEAD Filed April 16, 1964 3 Sheets-Sheet 2 FIG.5

HANS WESSEL INVENTOR.

BY (Kw Attorney Feb. 22, 1966 H. WESSEL 3,235,899

VACUUM CLEANER HEAD Filed April 16, 1964 5 Sheets-Sheet 5 FIG.7

F|G.6 HANS WESSEL INVENTOR.

Attorney United States Patent C) 3,235,899 VACUUM CLEANER HEAD HansWessel, Cologne, Germany (5525 Wildbergerhutte, Bezirk Cologne, Germany)Filed Apr. 16, 1964, Ser. No. 360,335 Claims priority, applicationGermany, Apr. 27, 1963, W 34,373; Jan. 29, 1964, W 36,077 4 Claims. (Cl.15365) The invention relates to a universal cleaning appliance usableeither for beating carpets or for brushing or vacuum-cleaning carpetsand floors. To this end, the underside of the appliance is equipped withbrush bars which may be withdrawn into the housing, further rotatablebrush rollers, beater bars vibrated by the suction air current, and asuction nozzle, wherein, by the selective switching of some of theseelements, some such elements may be switched off and others may beswitched on. The appliance has preferably rollers enabling it to beguided over the surface to be cleaned. Near one long edge, aconventional Vulkollan comb may be provided.

For the operation of the appliance, for example, a brush bar may bepushed out of the slot for the brushing operation. In order to switchoff the heating elements, during this operation, a valve is provided inthe articulated part of the connecting socket to the vacuum cleanerconduit for closing the suction air current against the suc tion airorifice for the heating elements, and connecting it to the suctionnozzle. During this operation, the brush bar and the brush roller areoperated, and the loosened dirt is sucked into the suction nozzle.

For pure suction operation, the brush bar is withdrawn into the housingso that only the Vulkollan comb and the two brush rollers protrudebeyond the lower surface and are effective. The appliance may be thenused for vacuum cleaning carpets as a normal carpet cleaner, or forcleaning floors by sucking up the dirt.

If the appliance is to be used as carpet beater, the valve is reversedso that the suction nozzle is closed and the suction air current isdrawn through the beater orifice, causing the beater elements to bevibrated because of the suction of the flow of air, over the bar, and tobeat the carpet.

According to the invention, the switching of the appliance from suctionto pure beating operation by means of a valve is a very simpleoperation, and has the further advantage that the appliance may be movedover the surface to be treated always in the same position. Theappliance according to the invention need not be rotated through 360 inorder to deflect the air suction current so as to switch from suction tobeating.

The outer rim of the appliance is an isosceles trapezium with wideleading edge and slightly inclined two side edges. This configurationhas the advantage of making possible better evacuation also in cornersthan with an appliance with rectangular outline.

In a further embodiment of the subject-matter of the invention, insteadof the two brush rollers on the underside of the cleaning appliance oneor more combs can be disposed in recesses or slots of the appliancehousing which take over the task of the rotating brush rollers.

In the practical development of this universal cleaning appliance it hasbeen seen that by the beating action alone, the dirt, and in particularthe cottons, threads and similar textile elements, cannot be providedadequately with suction, and accordingly brush rollers have beenprovided which are loosely and rotatably disposed and the task of whichis to loosen up such threads and the like and pull them up out of thecarpet as the appliance moves over it, and accordingly during thesubsequent beating and suction operation these threads can besubstantially completely removed from the carpet.

ice

With these brush rollers, the loosened threads may adhere to the brushesof the brush rollers or in particularly unfortunate cases even windround the brush rollers and become fixed with the result that blockageclamping or even locking of the rollers can arise, in time. The brushrollers can be cleaned by hand, but this is very inconvenient, as theoperator is forced to remove the separate threads from the brushrollers.

The comb used instead of the rollers may have a serrated edge on theside towards the carpet, or in a preferred embodiment may have a wavycontour, and consists of resilient material, such as Vulkollan. It canbe adjusted in height inside the slot in the appliance.

In particular, the comb is resiliently borne in the slot, so that on acertain pressure, and this can be quite light, of the appliance onto thecarpet the comb is pressed onto this and with the movement back andforth of the appliance over the carpet the projecting serrated edge ofthis comb loosens up any threads and places them to a position in whichby the subsequent beating and suction operation they are removed fromthe carpet.

According to a further embodiment of the invention the beating barsconsist of elastic bands.

It has been found that on occasion, due to the effect of certainelements on the vibration of the elastic bands, these, on vibrating, aresucked up by the suction flow of the air into the suction slit above thesaid bands, and become firmly wedged in this slit, so that the beatingeffect is cancelled out. This disadvantageous effect can it is true beavoided by switching the vacuum off for a short time, so that thesuction effect is broken off and the elastic bands are released from theopening of the suction slit and return to their original, flat position,but the trouble can be repeated and can lead to inconvenientinterruption of the cleaning.

Apparently this phenomenon results from the fact that-possibly quite bychance or because of certain vibration conditionsthe bands vibratesynchronously, even if only for a period, and furthermore, have the sameamplitude, so that all the bands to a certain extent function as asingle broad band and are sucked into the suction opening by the airstream.

To overcome these disadvantages, the separate bands are made of materialof various elastic strengths, that is to say some bands are lessstrongly elastic than others, and as a result of this their vibrationsas far as concerns vibration number or frequency, phase and amplitude,are different, and the possibility of there arising the abovementionedphase and amplitude synchronisation is not very likely.

A further solution offered by the invention is to manufacture theseparate bands of the same elastic material, of equal elasticity andelastic strength, but to make them of differing lengths, and so toadjust them in relation to each other while not yet installed in theappliance that in the stretched position of one or more bands, otherbands sag a little because of their greater length. When the bundle ofbands is installed in the appliance and stretched a little, even thebands which were sagging in unstressed condition will be stretched to acertain extent, but, however far the stretching process is carried on,will remain either sagging a little or, some of them, will flattenthemselves out. However, as some of the bands are strongly tensioned,othersthe bands which originally were sagging a littleare subjected tosomewhat lesser tension, and the separate bands will not only havediffering phase vibrations but also differing amplitudes, andaccordingly the danger of all the bands being simultaneously lodged inthe slot by the suction effect is reduced.

The invention provides furthermore the further possibility of preventingthe wedging action of the suction,

by disposing on both sides of the suction slit which is above the bends,ribs, shoulders and projections of this nature, so that one band or afew bands collectively rest on the support during the vibrating. Thismeans that, on the arisingof synchronisation of phase and amplitude, theblocking to a certain extent of the suction mouth by all the bands isavoided. The bands, in this maximumstate vibration i.e. maximumamplitude, are spaced from each other so that there is sufficient spacebetween the separate bands for the air to enter, and the suction lock?ing of the bands is thereby avoided. It is of significance here that bythis, the suction effect is at the same time intensified, as because ofthe differing tensions and elasticities in the beating bands and onaccount of the webs or projections for the support of the separatebands,the amplitude is. even greater than. with'the elastic bands of the mainpatent. Thus, with one and the same measure, the double advantage of theprevention of sucking up, and the preventingof interruption of thebeating effect is achieved on the one hand, and an increase in thebeating effect on the other hand.

The invention will be further described, by way of example, withreference to the accompanying drawing in which:

FIGURE 1 is a top,plan view;

FIGURE 2 is a side view;

FIGURE 3 is a bottom view;

FIGURE 4 is a partial cross-section of the lower part of the appliancewithin the zone of the beater bars along the line IV--IV in FIGURE 3with a semi-circular section of. the beater bars;

FIGURE 5 is a similar-partial cross-section with trap ezoidally shapedbeater bars;

FIGURE 6 is a similar cross-section with beater bars arranged one abovethe other;

FIGURE 7 is an embodiment similar to FIGURE 5 in which the two .beaterbars. have a triangular cross-section;

FIGURE 8 is a bottom view of the cleaningappliance;

FIGURE 9.is an elevation of the comb in part section along the line IXIXof FIGURE 8;

FIGURE 10 is a side elevation of the bundle of-bands in. untensionedstate showing bands of differing lengths;

FIGURE 11 is the same side elevation but with the bands tensioned;

FIGURE 12 is a cross-section through the appliance along the line XIVXIVof FIGURE'8';

FIGURE 13 is a longitudinal section through the ap: pliance along theline XIIIXIII of FIGURE 8 in accordance with a further embodiment of theinvention, in which the support webs are disposed on both sides of theslot sucking up the bands;

FIGURE 14 is a partial cross-section along the line XIVXIV of FIGURE 8but in the variant with webs;

FIGURE 15 is a partial bottom view of the appliance in the region of theelastic bands after installation of the bands in the appliance; and

FIGURE 16 is a longitudinal section similar to FIG- URE 13 but with'support shoulders for the elastic bands instead of the webs.

The cleaning appliance according to FIGURES 1 to 7 consists ofseveraLparts, made preferably of a hard thermoplastic, such as, forexample, shockproof polystyrene. These parts are the lower part 1, andtheupper part 3,

Near its leading edge 4, the flat housing 1 has two slide plates 5,engaging into slots inthe bottom of the lower part, and screwed to thebottom part by means of counter-sunk slotted-head screws 8. Between theslide plates, there is located a Vulkollan comb 10 which is mounted inpins. In the four corners of the-lower part 1 of the appliance, having atrapezoidal outline, there are rollers 13. Behind the guide plates,there is a suction nozzle 14 extending over the entire width of theunderside of the appliance which becomes flatter towards the narrowsides 15. Towards the center, a suction slot 18 is formed in the bottomof this groove. Substantially centrally, there are located insemi-cylindrical recesses brush rollers 20 which are freely rotatable onstub axles 21 in respective bearings.

Further towards the rear, there are two or more vibratory bands 23,-extending over the entire width of the appliance, and mounted at theirend by clips 24 so in a channel 25 on theunderside of the appliance thatthese bands are spaced at a certain distance from the passage at thebase of this groove when they are in the rest position (FIGURE 4)..

Yet further towards the rear of the appliance, near the edge 28, thereis a retractable brush bar 3t), disposed in a slot and likewiseextending over practically the entire width of. theappliance, which maybe pushed out of this slot at choice.

Finally, nearthe rear edge.28, there is a similar guide plate, 31, butextending over the. entire width. of the appliance and can. be fitted bymeans of tongues 32 into slots in the underside of the appliance,where-it is fixed by slottedhead screws 34. The three slide. plates 5,31 are of metal in contrast to the rest of the parts of the appliance,in order toprevent theappliauce from acquiring an electrostatic chargedue to friction.

During the beatingoperation, air is suckedin only through the slit 38.The air current, flowing between and outside the beater bars 23 from thebottom through the slit 38, causes the elastic beater bars 23 toapproach this opening 38. The increasing elastic tension in theseresilient. flexible members. gives. rise to a counter-acting forcewh-ich'st'ops the deflection of these bars in thedirection towards thesuction slit 38.. Owing to the changing flow resistances, the innertensions in .the beater bars, and the mass etfect, there occur fastvibratory movements which produce the beating effect.

The beater bars 23 have a semi-circular profile, cause ing a variationof the vibratory movement, since the flow conditions with these profilesdiffer.

The semi-circular. profiling of the beater bars has the advantage thatsuction fixing at the base of the slit 38 cannot so easily take place,as the air, on account of the arching on the rear side of the beaterbars, can still very easily pass between the not always completelyjuxtaposed edges of the two beater bars, and said bars accordingly donotwedge together by suction as in practice they can touch each other onlyon a narrow edge on the front side.

According to the embodiment shown in FIGURE 5,

thebeaterbars 49 have an irregular trapezoidal cross-sectionalconfiguration so that the facing edges of the trapez'ium 50 'havebetween them a narrow slot of uniform width'when they are at rest. Byreason of this trapezoidal shape, there occurs during thevibration inthe direction of the twin arrow 51 an impact between the two surfaces50, because the vibratory movements of the twobeater bars is notuniform. This givesrise to pressure forces 52 on the twosurfaces 50' ofvariable magnitude. These pressures cause the beater bars 49 to haveadditional side vibrations not only in the direction of the twin arrow51, but also normal thereto, that is to say, horizontally in thedirection of the twin arrow 53.

' This has the advantage that the beater movements take place not onlyvertically to the bars, but thatv additionally to-this purely beatingmovement a movement in the horizontal plane 53 is carried out. Inconsequence, there results a particularly good beating action andcleaning of the carpet, and suction fixing at the .base 22 of the slitis avoided, since the air can still penetrate into the slot 50' openingbetween the two obliquely running surfaces 52, 5

Accordingto the embodiments of FIGURE 6 the two beater bars 54, 55 areformed by flat bars, one above the other, of which the upper bar 55has acentre slot 56 and the lower bar 54 hasa width 57 which is smaller thanthat of the upper bar. This construction produces special beatingeffects because the air current has the flow shown at 58 in FIGURE 6.The heating effect is particular, be-

cause the two beater bars do not pass through a synarise only at thepoints 60 between the side walling 6t) and the beater bars. The currentof air, therefore, as can be seen from the arrows, has a large spaceavailable, particularly at the left beater bar, between the corner 60and the lower surface 27, so that the danger of suction fixing can bechecked.

These beater bars are of an elastic material, such as particularly softrubber, having preferably a Shore hardness of 50 to 60. The two bars mayalso be made of rubber materials having different Shore hardness so thatthe vibrations of both beater bars are different and can be adjusted oneto the other, in order to produce particular favourable beating effects.

In the embodiments of FIG'URES 8 and 9, instead of the brush rollers 20of FIGURE 3, a comb 1 made of Vulkollan is inserted in a slightly archedslot 2' of the housing 3' of the cleaning appliance. The slight archingof the slot 2' is for the purpose of ensuring that, with the uprighting,scratching or scraping action on the separate threads, these are betterput in the way of the beater bars 4'.

The scraper comb 1' has undulations 6 on the outside edge 5, and alsoseparate hook-like formations 7 by which it is hooked on to the interiorof the appliance on projections. In the vicinity of the two end regions,by flat triangular punc'hings 8', fiat angular spring means 9 are formedfrom angularly adjoining struts, with the pointed teeth of which thecomb abuts on the base 11 of the housing. In untensioned state the comb1 projects, by an extent shown at 12 out beyond the slot 2' of theappliance housing 3'. When the appliance is set on the carpet, thisdistance 12' is reduced by the pressing, and the comb is partiallypressed back into the interior of the housing, this being possiblebecause the springy parts 9 of the comb are deformable and take up aposition something similar to that shown in dotted lines in FIG- URE 9.

By the undulated shape of the outer edge on the one hand, and the easyde-formability of the comb on the other, the carpet in being treated inthis way is not only protected but care is moreover taken that thethreads, simply because this protective treatment, due to the lightpressure are better loosened from the carpet and made to stand on end aswas the case with the previously used brush rollers. The advantage ofthe comb of the invention furthermore consists in that it does not haveto be subsequently cleaned, as was the case with the brush rollers, asno hairs or threads or other dirt can attach themselves to the comb.

The two outer bands, of the elastic bands 4- as can be seen in FIGUREare, in tensioned state, shorter than the middle band, so that in thestretched position of the outer bands 4' this band sags a little. Whenthe bands with their clamps 14 are installed in the recess 16 of theappliance housing 3 they have to be stretched for this purpose, asFIGURE 11 shows by the arrow and by this action, the middle band shownin dotted lines in FIG- URE l1 straightens itself out a little from thehanging down position of FIGURE 10, so that the sagging is now veryslight. This position in the mid-region can be seen in cross-section inFIGURE 12.

In the embodiment of FIGURES 13 to 15 on both sides of the suctionchannel 17' disposed underneath the bands there are provided Webs 19 onthe base 13' of the recess 16' of height and width such that only thetwo outer bands 20' in vibrating, come to rest on them below, therebybeing restricted in amplitude from below, whereas the middle elasticband 21' can vibrate unimpeded with greater amplitude between the twowebs 19. This ensures that on unfavourable conditions arising, two oreven all the bands simultaneously, shall not vibrate up into the mouth22' of the suction channel 17' and completely close this mouth,remaining sucked in it.

With the embodiment with the webs it is not essential to have differingelasticity for the separate bands; on the contrary, all three bands canbe manufactured of equally elastic material and can have the samelengths when extended, so that in the tensioned state the three bandshave the same inner tension, and even so it is possible very effectivelyto prevent the suction fixing, byv the arrangement of the shoulders orwebs.

It can be expedient in accordance with the invention, for reasons ofadjustment possibilities, to adjust the height of the webs 19' inaccordance with the double arrow 23', and, further, the clamps 14 can beheight adjustable in the recess 16' of the housing 3 in accordance withdouble arrow 24, as a result of which the part 26 of the bands,projecting over the under edge 25', can, on the vibrating of the elasticbands, be adjusted, and according th beating effect also.

FIGURE 16 shows that the projecting part 26' of the bands can be madelarger if the clamps 14' are pushed in nearer to the under edge 25' ofthe housing, this being done by means of the adjusting screw 27'.

Instead of the webs 19', the recess 28' for the bands 20, 21' on bothsides of the mid-suction slit 29 can have stepped shoulders 34), and bythis, in a way similar to that achieved with the webs 19', some of theelastic bands are restricted in amplitude whereas others can vibrate upto the mouth of the slit 31. This possible embodiment affords a widersurface in the restricting of amplitude, these surfaces being shown inFIGURE 16 by the arrow 31'.

I claim:

1. A vacuum-cleaner head connectable with the suction line of a vacuumcleaner and selectively operable for vacuuming and beating carpets, rugsand like surfaces to be cleaned, said head comprising:

a generally flat housing connectable with said suction line and having abottom face juxtaposable with the surace to be cleaned;

means forming a suction nozzle in said face extending longitudinallytherealong transverse to the direction of movement of said head;

a longitudinally extending channel formed in said face and openingthereat while being transverse to said direction;

duct means for selectively connecting said nozzle and said channel tosaid suction line for inducing a flow of air alternatively through saidnozzle and said channel, said duct means including a passage formed insaid housing and communicating with said channel at a location spacedfrom the mouth thereof and from said face;

a plurality of elongated flexible resilient members in said channelanchored at the ends thereof while spanning said mouth and having acollective breadth at least equal to the width of said passage; at leastone of said flexible members upon its moveflexible members and saidlocation for intercepting at least one of said flexible members upon itsmovement in the direction of said location for preventing jamming ofsaid passage by said flexible members;

and a comb member extending longitudinally across said face and movablyreceived therein, said comb member having a multiplicity of projectionsalong a lower longitudinal edge engageable with said surface forloosening recrement thereon, and spring means in a one-piececonstruction with said projections for biasing said comb memberdownwardly from said face into engagement with said surface, saidprojections constituting a sinuous surface of said longitudinal edge,said comb member being composed of resilient material and being of bowedconfiguration, said spring means including a pair of spring memberslongitudinally spaced apart along said comb member and each constitutedby a pair of angularly adjoining struts depending from the comb member,said comb member further having hook-like portions engageable with saidhousing for retaining said comb member therein.

2. A vacuum-cleaner head as defined in claim 1 wherein said flexibleresilent members have different natural frequencies of oscillation.

3. A vacuum-cleaner head connectable with the suction line of a vacuumcleaner and selectively operable for vacuuming and beating carpets, rugsand like surfacesto be cleaned, said head comprising:

a generally flat housing connectable with said suction line and having abottom face juxtaposable with the surface to be cleaned;

means forming a suction nozzle in said face extending longitudinallythe'realong transverse to the direction of movement of said head;

a longitudinally extending channel formed in said face and openingthereat While being transverse to said direction;

duct means for selectively connecting said nozzle and said channel tosaid suction line for inducing a flow of air alternatively through saidnozzle and said channel, said duct means including a passage formed insaid housing and communicating with said channel at a location spacedfrom the mouth thereof and from said face;

a plurality of elongated flexible resilient members in said channelanchored at the ends thereof while spanning said mouth and having acollective breadth at least equal to the width of said passage;

at least one formation in said channel between said flexible members andsaid location for intercepting at least one of said flexible membersupon its movement in the direction of said location for preventingjamming of said passage by said flexible members;

and a comb member extending longitudinally across said face and movablyreceived therein, said comb member having a multiplicity of projectionsalong a lower longitudinal edge engageable with said surface forloosening recnement thereon, and spring means in a one-piececonstruction with said projections for biasing said comb memberdownwardly from said face into engagement with said surface, at leastthree of said flexible resilient members being-provided and at least twoof said flexible'mem-bers being engageable with respective ones of saidformations for preventing jamming of said flexible members in saidchannel.

4. A vacuum-cleaner head as defined in claim 3 wherein said projectionsconstitute a sinuous surface ofsaid longitudinal edge, said comb memberbeing composed of resilient material and being of bowed configuration,said spring means including a pair of spring members longitudinallyspaced apart along said comb member and 'each constitutedby a pair ofangularly adjoining struts depending from the comb member, said combmember further having hook-like portions engageable with said housingfor retaining said comb member therein.

References Cited by the Examiner UNITED STATES PATENTS 2,314,081 3/1943Dow et a1. 15-402 X 2,717,409 9/1953 Draudt 15-402 X 2,858,561 11/1958Kuppersmith 15-382 3,002,217 10/1961 Smithson et a l. 1537l X FOREIGNPATENTS 1,253,699 1/1961 France. 1,256,786 2/1961 France. 6

315,177 7/1929 Great Britain.

856,602 12/ 1960 Great Britain.

901,575 7/1962 Great Britain.

ROBERT W. MICHELL, Primary Examiner.

-CHARLES A. WILLMUTH, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,235,899 February 22, 1966 HansWessel ified that error appears in theabove numbered pat- It is hereby cert ion and that the said LettersPatent should read as ent requiring correct corrected below.

strike out "of said flexible members upon Column 6, line 62,

formation in said channel between its move-"and insert instead saidSigned and sealed this 10th day of October 1967.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

1. A VACUUM-CLEANER HEAD CONNECTABLE WITH THE SUCTION LINE OF A VACUUMCLEANER AND SELECTIVELY OPERABLE FOR VACUUMING AND BEATING CARPETS, RUGSAND LIKE SURFACES TO BE CLEANED, SAID HEAD COMPRISING: A GENERALLY FLATHOUSING CONNECTABLE WITH SAID SUCTION LINE AND HAVING A BOTTOM FACEJUXTAPOSABLE WITH THE SURFACE TO BE CLEANED; MEANS FORMING A SUCTIONNOZZLE IN SAID FACE EXTENDING LONGITUDINALLY THEREALONG TRANSVERSE TOTHE DIRECTION OF MOVEMENT OF SAID HEAD; A LONGITUDINALLY EXTENDINGCHANNEL FORMED IN SAID FACE AND OPENING THEREAT WHILE BEING TRANSVERSETO SAID DIRECTION; DUCT MEANS FOR SELECTIVELY CONNECTING SAID NOZZLE ANDSAID CHANNEL TO SAID SUCTION LINE FOR INDUCING A FLOW OF AIRALTERNATIVELY THROUGH SAID NOZZLE AND SAID CHANNEL, SAID DUCT MEANSINCLUDING A PASSAGE FORMED IN SAID HOUSING AND COMMUNICATION WITH SAIDCHANNEL AT A LOCATION SPACED FROM THE MOUTH THEREOF AND FROM SAID FACE;A PLURALITY OF ELONGATED FLEXIBLE RESILIENT MEMBERS IN SAID CHANNELANCHORED AT THE END THEREOF WHILE SPANNING SAID MOUTH AND HAVING ACOLLECTIVE BREADTH AT LEAST EQUAL TO THE WIDTH OF SAID PASSAGE; AT LEASTONE OF SAID FLEXIBLE MEMBERS UPON ITS MOVEFLEXIBLE MEMBER AND SAIDLOCATION FOR INTERCEPTING AT LEAST ONE OF SAID FLEXIBLE MEMBERS UPON ITSMOVEMENT IN THE DIRECTION OF SAID LOCATION FOR PREVENTING JAMMING OFSAID PASSAGE BY SAID FLEXIBLE MEMBERS; AND A COMB MEMBER EXTENDINGLONGITUDINALLY ACROSS SAID FACE AND MOVABLE RECEIVED THEREIN, SAID COMBMEMBER HAVING A MULTIPLICITY OF PROJECTIONS ALONG A LOWER LONGITUDINALEDGE ENGAGEABLE WITH SAID SURFACE FOR LOOSENING RECREMENT THEREON, ANDSPRING MEANS IN A ONE-PIECE CONSTRUCTION WITH SAID PROJECTIONS FORBIASING SAID COMB MEMBER DOWNWARDLY FROM SAID FACE INTO ENGAGEMENT WITHSAID SURFACE, SAID PROJECTIONS CONSTITUTING A SINUOUS SURFACE OF SAIDLONGITUDINAL EDGE, SAID COMB MEMBER BEING COMPOSED OF RESILIENT MATERIALAND BEING OF BOWED CONFIGURATION, SAID SPRING MEANS INCLUDING A PAIR OFSPRING MEMBERS LONGITUDINALLY SPACED APART ALONG SAID COMB MEMBER ANDEACH CONSTITUTED BY A PAIR OF ANGULARLY ADJOINING STRUTS DEPENDING FROMTHE COMB MEMBER, SAID COMB MEMBER FURTHER HAVING HOOK-LIKE PORTIONSENGAGEABLE WITH SAID HOUSING FOR RETAINING SAID COMB MEMBER THEREIN.